An amount of signal transmitted via a wireless communication network is constantly increasing. In the near future, a signal of which a volume is several times greater than currently used signals will be transmitted via the wireless communication network.
Recently, a technology that improves efficiency in data transmission using a relay has been introduced. The relay receives data from a base station using the downlink sub-frame, and transmits the received data to a terminal using another downlink sub-frame.
Accordingly, the base station may transmit a control channel with respect to the relay, as well as a control channel with respect to the terminal, using a downlink sub-frame. Since a number of control channels to be transmitted via a downlink is increased, there is a desire for a method of efficiently transmitting the control channels.